NORTHWEST NATURAL GAS COMPANY
P.U.C. Or. 24
Ninth Revision of Sheet 190-1
Cancels Eighth Revision of Sheet 190-1
SCHEDULE 190
PARTIAL DECOUPLING MECHANISM
PURPOSE:
To (a) describe the partial decoupling mechanism established in accordance with a Stipulation and
Agreement adopted by the Oregon Public Utility Commission (OPUC) in Docket UG 143, Order No.
02-634, dated September 12, 2002, and later reauthorized, with modifications, in Docket UG 163,
Order No. 05-934, dated August 25, 2005; and (b) identify the adjustment applicable to rates under
the Rate Schedules listed below.
TERM:
This Schedule shall automatically terminate on October 31, 2012, or on such other date as the
Commission may approve.
APPLICABLE:
To Residential and Commercial Customers served on the following Rate Schedules of this Tariff:
Residential
Schedule 1
Schedule 2
Commercial
Schedule 1
Schedule 3(SF)
Schedule 31(SF)
Schedule 31(SI)
Schedule 31(TF)
Effective: November 1, 2008
ADJUSTMENT TO RATE SCHEDULES:
The Temporary Adjustments for Residential and Commercial Customers taking service on the abovelisted Rate Schedules includes the following adjustment:
Residential Rate Schedules:
Commercial Rate Schedules:
$ 0.00214 per therm
$(0.01546) per therm
PARTIAL DECOUPLING DEFERRAL ACCOUNT:
1. Each month, the company will calculate the difference between weather-normalized usage and
the calculated baseline usage for each Residential and Commercial Customer group. The
resulting usage differential shall be multiplied by the per therm distribution margin for the
applicable customer group.
The Company shall defer and amortize, with interest, 100% of the distribution margin differential
in a sub-account of Account 186. The deferral will be a credit (accruing a refund to customers) if
the differential is positive, or a debit (accruing a recovery by the company) if the differential is
negative.
(continue to Sheet 190-2)
Issued October 21, 2008
NWN Advice No. OPUC 08-5C
Effective with service on
and after November 1, 2008
Issued by: NORTHWEST NATURAL GAS COMPANY
d.b.a. NW Natural
220 N.W. Second Avenue
Portland, Oregon 97209-3991
NORTHWEST NATURAL GAS COMPANY
P.U.C. Or. 24
Eighth Revision of Sheet 190-2
Cancels Seventh Revision of Sheet 190-2
SCHEDULE 190
PARTIAL DECOUPLING MECHANISM
(continued)
PARTIAL DECOUPLING DEFERRAL ACCOUNT (continued):
2. The baseline usage shall be determined from actual weather normalized usage for the
Company’s most recent rate case, as adjusted for any price elasticity effects since that rate case.
The following is an example baseline usage calculation for the Residential Group:
Weather-normalized usage, divided by
Residential Customers, equal
330,164,716
450,709
Normalized use per therm per customer
October 1 price decrease
Usage increase due to price elasticity (-10% x -0.172)
Estimated usage increase due to price elasticity
(weather normalized usage x % of usage increase)
Total New Baseline Usage: (weather normalized usage plus
estimated usage increase), divided by
customer count, equal
733
-10%
1.72%
5,678,833
335,843,549
450,709
745
Reset baseline usage per therm per customer
3. Weather-normalized usage is calculated using the approach to weather normalization adopted in
the Company’s last general rate case, Docket UG 152. The weather data is taken from the
stations identified in RULE 24.
Step One. For the heating season months October through May, usage is normalized by taking
the difference between normal and actual heating degree days for each district using a base of 59
degrees for Residential and 58 degrees for Commercial.
Step Two. This step derives the per-therm customer variance by multiplying the heating degreeday difference by the usage coefficient of .1958 for Residential variances, and .7669 for
Commercial variances.
Step Three. The per-therm customer variance is multiplied by the appropriate customer count, by
district, with the sum of the district results representing the normalized therm amount.
4. Baseline usage will be adjusted to reflect actual customers billed each month.
5. The per therm distribution margins to be used in the deferral calculation effective January 1, 2009
is $0.43350 per therm for Residential customers and $0.29701 per therm for Commercial
customers.
(continue to Sheet 190-3)
Issued November 17, 2008
NWN Advice No. OPUC 08-10
Effective with service on
and after January 1, 2009
Issued by: NORTHWEST NATURAL GAS COMPANY
d.b.a. NW Natural
220 N.W. Second Avenue
Portland, Oregon 97209-3991
NORTHWEST NATURAL GAS COMPANY
P.U.C. Or. 24
First Revision of Sheet 190-3
Cancels Original Sheet 190-3
SCHEDULE 190
PARTIAL DECOUPLING MECHANISM
(continued)
PARTIAL DECOUPLING DEFERRAL ACCOUNT (continued):
6.
Coincident with the Company’s annual Purchased Gas Cost and Technical Rate Adjustment filing
commencing with the filing effective October 1, 2003, and each year thereafter during the term of
this Schedule, the Company shall apply an adjustment to Residential and Commercial rates to
amortize over the following 12 months, the balance in the balancing account as of June 30.
7.
This Schedule is an "automatic adjustment clause" as defined in ORS 757.210, and is subject to
review by the Commission at least once every two (2) years.
SPECIAL CONDITIONS :
1.
The existence of this Partial Decoupling Mechanism will not affect the Company’s service line and
main extension policies.
2.
Other terms and conditions as specified in the Stipulation and Agreement.
GENERAL TERMS:
This Schedule is governed by the terms of this Schedule, the General Rules and Regulations
contained in this Tariff and by all rules and regulations prescribed by regulatory authorities, as
amended from time to time.
Issued September 12, 2005
NWN Advice No. OPUC 05-9A
Effective with service on
and after October 1, 2005
Issued by: NORTHWEST NATURAL GAS COMPANY
d.b.a. NW Natural
220 N.W. Second Avenue
Portland, Oregon 97209-3991